LOCATION SAUVOLA WAEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Ultic Palexeralfs
TYPICAL PEDON: Sauvola silty clay loam - under a 7 to l0 year old Douglas-fir stand on a l0 percent convex northeast facing back slope at an elevation of 400 feet. (The soil was moist when described. Colors are for dry soil unless otherwise noted. All textures are apparent field textures.)
Oe--l inch to 0; partially decomposed organic litter including charcoal; abrupt smooth boundary. (0 to 3 inches thick)
A--0 to l0 inches; very dark grayish brown (l0YR 3/2) silty clay loam, light brownish gray (l0YR 6/2) dry; weak fine subangular blocky structure parting to medium granular; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine, and medium, common coarse roots; many very fine irregular pores; 5 percent shot- like aggregates (2-5 mm in diameter), 2 percent hard, rounded pebbles; moderately acid (pH 6.0); clear wavy boundary. (6 to l5 inches thick)
ABt--l0 to l8 inches; dark brown (l0YR 3/3) silty clay loam, pale brown (l0YR 6/3) dry; weak fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine, medium, and coarse roots; many very fine tubular pores; few faint clay films on some peds; 2 percent hard, rounded pebbles; moderately acid (pH 5.6); clear wavy boundary. (0 to l2 inches thick)
Bt1--l8 to 26 inches; brown (l0YR 5/3) silty clay loam, light gray (l0YR 7/2) dry common medium distinct yellowish brown (l0YR 5/6) mottles, brownish yellow (l0YR 6/6) dry; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine, fine, medium and coarse roots; many tubular pores; many distinct clay films on peds and in pores; strongly acid (pH 5.4); clear wavy boundary.
Bt2--26 to 32 inches; brown (l0YR 5/3) silty clay, white (l0YR 8/2) dry; many fine and medium distinct yellowish brown (l0YR 5/8) mottles, brownish yellow (l0YR 6/8) dry; moderate fine and medium angular blocky structure; hard, firm, sticky and slightly plastic; common fine, medium and coarse roots; common fine tubular pores; many prominent clay films on peds and in pores; strongly acid (pH 5.2); clear wavy boundary.
Bt3--32 to 43 inches; brown (l0YR 5/3) silty clay, very pale brown (l0YR 7/3) dry; few fine distinct yellowish brown (l0YR 5/8) mottles, brownish yellow (l0YR 6/8) dry; moderate coarse subangular blocky structure; very hard, very firm, sticky and plastic; few roots; common fine tubular pores; continuous prominent clay films on peds and in pores; very strongly acid (pH 4.8); clear wavy boundary. (Combined thickness of the Bt horizon is 18 to 34 inches)
BC--43 to 60 inches; brown (l0YR 5/3) silty clay, very pale brown (l0YR 7/3) dry; few fine distinct yellowish brown (l0YR 5/8) mottles; brownish yellow (l0YR 6/8) dry; massive; hard, firm, sticky and slightly plastic; few roots; very strongly acid (pH 5.0).
TYPE LOCATION: Lewis County, Washington; about 7.5 miles east of Toledo, l00 feet south of Weyco logging road #l800; 600 feet east and 925 feet south of the northwest corner of sec. 2l, T. ll N., R. l E.
RANGE IN CHARACTERISTICS: Average annual soil temperature at a depth of 20 inches ranges from 49 to 53 degrees F. These soils are usually moist but they are dry in all parts between depths of 4 and l2 inches for 45 to 60 consecutive days following the summer solstice. The particle-size control section contains 35 to 60 percent clay, 0 to l0 percent unweathered pebbles and 0 to l0 percent weathered pebble-size siltstone and sandstone fragments. Thin gravelly lenses are in some profiles.
The A horizon has value of 2 or 3 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. It is slightly acid to very strongly acid.
The AB horizon, and BA horizon when present, has value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. It is loam, silty clay loam, or silt loam. It is slightly acid to very strongly acid.
The Bt horizon has hue of 7.5YR through 2.5Y, value of 3 through 6 moist, 5 through 8 dry, and chroma of 2 or 6 moist and dry. Mottles have hue of l0YR or 5YR, value of 4 to 8 moist and dry, chroma of 2 through 8 moist and dry. It is silty clay loam, silty clay, or clay. It is moderately acid to very strongly acid.
The BCt horizon, when present, has value of 4 or 5 moist, 6 through 8 dry, and chroma of 2 or 3 moist and dry. Mottles have hue of l0YR or 7.5YR, value of 5 or 6 moist and dry, and chroma of 6 through 8 moist and dry. This horizon is silty clay loam or silty clay. It is strongly acid or very strongly acid.
COMPETING SERIES: These are the Melbourne, Munset, and Spreckles series. Munset soils are 20 to 40 inches deep to a lithic contact. Melbourne soils have no mottles in the argillic horizon. Spreckles soils are very gravelly in the lower part of the argillic horizon.
GEOGRAPHIC SETTING: Sauvola soils are on terraces and foothills at elevations of l50 to 900 feet. Slope is 0 to 30 percent. These soils formed in residuum, from non-marine micaceous siltstone of the Wilkes formation or old alluvium. The climate is marine and characterized by cool, dry summers and mild, wet winters. The average annual precipitation is 45 to 55 inches. The average January temperature is 39 degrees F.; the average July temperature is 66 degrees F.; and the average annual temperature is about 5l degrees F. The frost-free season (32 degrees F.) is l50 to 200 days. The growing season (28 degrees F.) is l75 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Melbourne soils and the Buckpeak, Centralia, Lacamas, Olympic, Prather, Scamman, and Seaquest soils. Buckpeak and Centralia soils are fine-loamy. Lacamas soils have an aquic moisture regime. Prather and Scamman soils have grayish mottles in the particle-size control section.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow to medium runoff; moderate permeability in the A and AB horizons and moderately slow in the Bt, and BCt horizons. A perched water table is as high as 1.5 to 3.5 feet at times during the winter and spring.
USE AND VEGETATION: Used for timber production, wildlife habitat, and watershed. Some areas are used for crop production and as homesites. Overstory vegetation is Douglas-fir, western redcedar, bigleaf maple, grand fir, and red alder with an understory of salal, red huckleberry, Oregongrape, western brackenfern, western swordfern, longtube twinflower, violet, western rattlesnake plantain, and vine maple.
DISTRIBUTION AND EXTENT: Puget lowlands in southwestern Washington. Southern Lewis County and Cowlitz County, Washington. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Cowlitz County, Washington, l97l.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the mineral surface to 10 inches, and an argillic horizon from 18 to 43 inches. Characterization data are available on this Series Lab number S84WA-015-010.